Two-cycle internal combustion engine fuel



3,251,661 TWO-CYQILE INTERNAL COMBUSTION ENGHNE FUEL James B. Retzloff and Joseph E. Kieninger, both of Royal Oak, Mich, assignors to Ethyl Corporation, New York, N.Y., a corporation of Virginia No Drawing. Filed Nov. 15, 1961, Ser. No. 152,677 15 Claims. (CI. 4458) This invention relates to a method of operating a twocycle internal combustion engine and to compositions having utility in this operation. More particularly, this invention relates to a method of operating a two-cycle engine wherein the lubricant is premixed with the fuel.

Spark ignition engines of the two-cycle type, which have no lubricant reservoir, are generally lubricated by including oil in the fuel which lubricate the engine and is eventually burned in the cylinders. When insufiicient oil is employed in the fuel-lubricant mixture, excessive engine wear results. However, fuel/oil ratios sufficient to prolong engine life in terms of wear adds greatly to the over-all cost of the petroleum hydrocarbon mixture necessary to operate the engine. Furthermore, the use of a satisfactorily low ratio of fuel/oil ratio from the wear standpoint usually leads to excessive deposition and drastic shortening of the life of the spark plugs in the engine. In overcoming the spark plug problem by increasing the fuel/oil ratio, the operation in turn leads to excessive engine wear. Heretofore it has not been possible to operate two-cycle engines with fuel/oil ratios much above 21/1 without encountering-catastrophically high rates of engine wear and indeed, without running the risk of actual seizing of the moving parts of the engine.

Modern practice in two-cycle operation, especially with respect to high performance outboard engines, is to use leaded fuels fuels containing alkyllead antiknock agents-to insure proper engine efiiciency and optimum power. The lead-containing .products formed by combustion in the engine of such alkyllead antiknocks substantially increase the magnitude of the problems outlined above in high fuel/oiloperation.

It is, therefore, an object of this invention to provide a method for operating a two-cycle internal combustion engine using an economically high fuel/oil ratio and at the same time keep engine wear at an acceptable level. A further object of this invention is to provide compositions useful in operating two-cycle spark-ignition internal combustion engines. Other objects will become apparent by the following description of. the invention.

It has now been found that two-cycle spark-ignition internal combustion engines may be satisfactorily operated at extremely high fuel/ oil ratios by employing the method and compositions of this invention. The method of this invention comprises operating a two-cycle spark-ignition internal combustion engine, which is normally lubricated by the lubricant added to the fuel, on a composition made up of leaded hydrocarbon fuel'of the gasoline type to which has been added a lubricant so that the weight ratio of fuel to lubricant ranges from about 15/1 to about 200/ 1, said composition also containing from 0.01 to 10.0 percent by weight, based on the weight of said lubricant, of an oil-soluble sulfur-containing organotin compound which has at least one carbon-to-tin bond and at least one non-ionic tin-to-sulfur bond. Such tin compounds, when used according to this invention, permit use of much higher fuel/oil ratios than heretofore, while at the same time minimizing or eliminating any wear increase due to the lower amount of oil relative to the amount of fuel.

The compositions used in the above method, namely, a fuel-oil mixture especially adapted for use in two-cycle engines, said fuel comprising leaded hydrocarbon fuel of United States Patent "ice the gasoline boiling range and said oil comprising hydrocarbon mineral oil, the weight ratio of said fuel to said oil being between about 15/ 1 and about 200/ 1, said composition containing an oil-soluble sulfur-containing 0rganotin compound having at least one carbon-to-tin bond and at least one non-ionic surfur-to-tin bond, also comprises an aspect of this invention. In addition, certain oil-additive combinations, described below, also make up part of this invention.

By leaded fuel we mean fuel containing from about 0.5 to about 6.0 grams of lead per gallon as an alkyllead antiknock compound, such as tetraethyllead, tetramethyllead, mixtures of tetramethyllead and tetraethyllead, the equilibrium mixtures of tetramethyllead, trimethylethyllead, dimethyldiethyllead, methyltriethyllead and tetraethyllead produced by chemical redistribution of tetraethylleadtetramethyllead mixtures, such as the 50 mol percent-50 mol percent mixture, the 25 mol percentmol percent mixture, the 75 mol percent-25 mol percent mixture, and so forth. Aryllead compounds, such as tetraphenyllead, can also be used.

Although a principal benefit of this invention is the great increase which it permits in fuel/oil ratio, it is found that good results are obtained when the compositions of this invention are used in fuel/oil ratios as low as about 15 1. However, it is to be emphasized that the major advantage of the present invention is that it permits the use of fuel/ oil ratios, in two-cycle operation, drastically higher than any heretofore realizable. Accordingly, a greatly preferred embodiment which constitutes a major advance over all past practice comprises the above compositions wherein the fuel/ oil ratio ranges upward from about 30/1 to about 200/1. Such extremely high fuel ratios have heretofore been unavailable, because of the problems of catastrophic wear and potential seizing of parts.

The particular fuel/oil ratios employed in any given situation depending upon the concentration of organotin compound employed and the severity of the engine operation. The more severe operating conditions generally call for lower fuel/oil ratios, and, for a given severity of 0pera tion, the fuel/ oil ratio necessary. for a given wear rate varies directly with the concentrations of organotin compound in the oil. The more organotin compound present, the higher the fuel/oil ratio can be for a given wear rate.

In other words, this invention permits use of fuel/oil ratios higher than heretofore without substantial sacrifice in engine wear, and alternately permits use of conventional fuel/oil ratios with substantial decrease in engine wear.

Among the organotin compounds which comprise the additives of this invention, the preferred compounds are dialkyl t-in sulfide, having the formula R SnS, Where R is a hydrocarbon radical of 3 to about 18 carbon atoms, including alkyl, cycloalkyl and aryl hydrocarbon radicals. Specific examples include dipropyl tin sulfide, dibutyl tin sulfide (n-iso-, sec-, tertand mixed) diphenyl tin sulfide, dilauryl tin sulfide, di(octadecyl) tin sulfide, and the like. Unsaturated radicals such as allyl can also be used although the preferred compounds are made up of saturated hydrocarbon radicals.

Of all the tin compounds of this invention dibutyl tin sulfides are preferred because of outstanding effective- When the alkyl radical in a dialkyl tin sulfide is methyl or ethyl the compound exists in a cyclic trimeric form (R SnS) These compounds, e.g., trimeric diethyl tin sulfide and trimeri-c dimethyl t-in sulfide, are also included in this invention.

Other compounds within the scope of this invention include triorganotin monosulfides having the formula (R Sn) S, where R is a hydrocarbon radical of 1 to 18 carbon atoms of the type described above. Examples include trimethyl tin monosulfide and tritolyl tin monosulfide. The triorgano-tin trisulfides, having the formula (RSn) S also are useful in this invention, R again being a hydrocarbon radical of the above type containing v1 to 18 carbon atoms. Examples include tricyclohexyl tin trisulfide and trixylyl tin trisulfide. In addition, the alkyl tin hydrosulfides, having the formula RSn(SH) again where R is as above, are likewise useful. Examples include butyl tin hydrosulfide and decyl tin hydrosulfide.

In addition to the above types of compounds any other oil-soluble sulfur-containing organotin compound having at least one carbon to-tin bond and at least one nonionic tin-to-sulfur bond may be used. Compounds having an ionic tin-to-sulfur bond, such as organotin sulfates, are not useful. One reason is that they do not have the requisite solubility properties.

Although certain organotin compounds have been suggested as additives to lubricant compositions and, when in such lubricant compositions, as upper cylinder lubricants, the present invention and its surprising features are completely unexpected.

For one thing, due to the high dilution of the oil with gasoline in the present compositions, the concentration of the active tin ingredient in the finished fuel can be miniscule and still permit the realization of the benefits of this invention. For another thing, the compositions of this invention serve two distinct functions in two-cycle operation. Not only do they perform the function of lubricating engine parts before the fuel is consumed in the combustion chamber, but they also serve to lessen wear in and near the combustion chamber itself during and after the fuel is burned, in spite of the lead combustion products which contribute to a wear-causing environment.

Instructions and references for preparation of many of the tin compounds of this invention are found in Krause and Von Grosse, Die Chemie der metallorganischen Verbindungen, Edwards Brothers, Inc., Ann Arbor, 1943.

The compositions of this invention can be prepared by forming an organotin sulfide-oil composition and adding it to leaded fuel, by forming an organotin sulfideleaded fuel composition and adding it to oil;or by forming an oil-leaded fuel composition and adding the organotin sulfide to it. The alkyllead compound can similarly be added to the fuel, to the oil, or to the fuel-oil combination. It is most preferable to add the organotin sulfide to hydrocarbon mineral oil, in concentration of about 0.1 to about weigh-t percent, and to add this organotin sulfide-oil composition to leaded fuel.

The lubricating oil employed in the compositions of this invention is generally a mineral lubricating oil of the type usually employed for the crankcase lubrication of a spark ignition internal combustion engine. Thus, 1t may be derived from parafiinic, naphthenic, asph-altic or mixed base stocks and in general, has a viscosity varying of the gasoline boiling range. However, it may, and often does, contain minor proportions of various other ingredients including non-hydrocarbon fuel constituents. Furthermore, the fuel always contains from 0.5 to about 6.5 grams of lead per gallon as an alkyllead antiknock agent of the type described above to improve the octane quality of the fuel. The compositions of this invention ordinarily but not always also contain one or more organic halide scavengers. The function of an organic halide scavenger is to convert the lead present in the combustion chamber, after combustion, to lead halide, which is more volatile and more easily exhausted from the engine than lead oxides,'which are the normal combustion products when scavengers are not used. The amount of scavenger employed is such as to provide from about 0.75 to 2.5 or more theories of halogen based on the amount of lead present. A theory of halogen is that amount which is required to quantitatively convert the lead present to lead dihalide. A common example, which is widely used in two-cycle service, is Motor Mix, which is a tetraethyllead fluid containing 1.0 theory of chlorine as ethylene dichloride and 0.5 theory of bromine as ethylene dibromide.

In this connection it has been found that addition to the compositions of this invention of organic halide scavengers in amount greater than normally used in gasoline provides great benefits in terms of reduced combustion chamber deposits and increased spark plug life. Thus, in one aspect of our invention we include in the finished composition an organic halide scavenger or mixture of such scavengers, so that the total amount of halogen present in the fuel/oil compositions is as high as 2.5 theories based on the amount of lead present. Ordinary gasoline seldom contains more than 1.5 or 1.6 total theories of halogen. This addition of extrascavenger can be conveniently done by blending the organic halide into the oil before the oil is blended with the fuel; into the finished fuel/oil composition; or into the fuel before the fuel is blended with the oil. In any event, the extra scavenger is added in such amount that the total present in thefinished fuel/ oil composition ranges from about 0.75 to 2.5 theories based on the amount of lead present.

It is usually preferable to blend the organic halide scavenger in the oil prior to addition to the fuel. Ordinarily, we blend so that the scavenger is present in the oil to the extent of about 0.5 to about 7.5 percent by Weight of the oil. Thus, an aspect of this invention comprises mineral lubricating oil containing 0.1 to 10.0 weight percent of an'organotin compound of the type described and an organic halide scavenger in amount sufiicient to substantially reduce combustion chamber deposit formation and increase spark plug life in the two-cycle engine. This amount of organic halide scavenger will usually range from about 0.25 to about 7.5 percent,'preferably 0.25 to 2.5 percent, by weight of the oil. Another embodiment of this invention includes fuel compositions containing oil with the above amounts of organotin sulfide and organic halide scavenger, wherein the fuel/oil ratio ranges from about 15/1 to about 200/ 1, preferably from about 30/1 to about 200/1.

Further examples of suitable organic halide scavengers for use in this invention include ethylene dichloride, propylene dichloride, chlorinated benzenes, brominated benzenes and toluenes, borminated propanes, butanes and ethanes. Further scavengers include carbon tetrachloride; propylene dibromide; 2-chloro-2,3-dibromobutane; 1,2,3- tribromopropane; hexachloropropylene; mixed brornoxylenesg 1,4 dibromobutane; 1,4 dichloropentane; ,8,,8'-dibromodiisopropyl ether; trichlorobenzene; dibromotoluenes; tert butyl bromide; 2 methyl 2 bromobutane; 2,3,3 trimethyl 2 bromobutane; tert butyl chloride; 2,3 dimethyl 2,3 dibromobutane; 2,3 dimethyl-2,5-dibromohexane; 2-methyl-2,3-dibromobutane; 2 methyl-2,3-dichloroheptane; 2-methyl-2,4-dibromohexane; 2,4-dibromopentane; 2,5-dichlorohexane; 3-methyl- 2,4-dibromopentane; l-phenyl-l-bromoethane; l-phenyl-lchloroethane; ethyl a bromoacetate; diethyl-dibromomalonate; propyl-a-chlorobutyrate; 1,1-dichloroJ1-nitroethane; 1,1-dichloro-2-nitroethane; 1,1-dibromo-1-nitrobutane; 2-chloro-4-nitropentane; 2,4-dibromo-3-nitropentane; 1-chloro-2-hydroxyethane; 1-bromo-3-hydroxypropane; 1-bromo-3-hydroxybutane; 3-methyl 2 bromo-4- hydroxypentane; 3,4-dimethyl-2-bromo-4-hydroxypentane; and, in general, scavengers disclosed in US. Patents 1,592,954; 1,668,022; 2,364,921; 2,479,900; 2,479,901; 2,479,902; 2,479,903 and 2,496,983. 1 Such products may be used singly or in combination. We prefer the bromohydrocarbons to the chlorohydrocarbons because the former are less corrosive to the aluminum parts which are widely used in two cycle engines. The most preferred compound in ethylene dibromide and we prefer to use this material in concentration of 0.25 to 2.0 percent in the oil or 0.75 to 2.5 theories in the finished fuel/ oil composition.

In a greatly preferred embodiment of this invention the fuel and oil compositions contain, in addition to the organotin compound, a detergent additive. Use of such a detergent leads to vastly superior results. Any hydrocarbon-soluble detergent can be used. This includes both the ash-forming type and the ashless type. Ordinarily, the ashless detergents, including surfactants, are preferred.

Examples of suitable detergents include the heavy metal salts of carboxylic or sulfonic acids and the metal alcoholates or phenolates, in all of which the anionic constituent has a large hydrocarbon-soluble radical. The metal constituent is usually an alkaline earth metal, most commonly calcium or barium. The aluminum, zinc and cobalt salts are also used. Other detergents include the metallic salts of the mahogany sulfonic acids, the alkyl phosphoric acids, the alkyl phenols, phthalic monoesters, alkylaryl phosphoroamides, long-chain phenolic ether alcohols, naphthenic acids, amino substituted fatty acids,

- chlorinated fatty acids and acids containing thioether groups.

Further examples of suitable detergents are the lecithins and various long-chain esters of polyhydric alcohols.

Further examples include reaction products of P 5 with olefins, terpenes and alcohols, as well as salts thereof, the calcium and barium petroleum sulfonates, the calcium and barium alkyl phenol sulfides and methacrylate polymers and co-polymers particularly polymers with vinyl pyridines and vinyl pyrrolidones. Vinyl caprolactams and vinyl valerolactams are also co-monomers used in forming such polymethacrylate detergents. Further useful detergents include polyhydrocarbons, such as low molecular weight polybutenes, and the polyoxyethylene derivatives of various polymers, such as amine-aldehycle, sulfonamide-aldehyde, phenol-aldehyde, alkyd, polyamide and imidazoline resins.

Detergent additives which cooperate in an outstanding way with the organotin additives of this invention include derivatives of carboxylic acids wherein an amide or imidazoline linkage exists. Especially outstanding are amides made from carboxylic acids of about 6 to about carbon atoms with secondary amines of about the same number of carbon atoms. Such amides have the general formula where R is an unsaturated or, more preferably, a saturated aliphatic radical of 5 to 9 carbon atoms and R and R are preferably saturated aliphatic or cycloaliphatic radicals of 6-10 carbon atoms. Such compounds wherein R and R are secondary aliphatic radicals are especially preferred. Thus, an aspect of this invention comprises mineral lubricating oil containing 0.1 to 10.0 weight percent of an organotin compound of the type described and a hydrocarbon-soluble detergent in amount sufficient substantially reduce sludge formation in the two-cycle engine. This amount of detergent will usually range from about 0.25 to about 10 percent, preferably 0.5 to 5 percent, by weight of the oil. Another embodiment of this invention includes fuel compositions containing oil with the above amounts of organotin sulfide and detergent, wherein the fuel/oil ratio ranges from about /1 to about 200/ 1, preferably from about 30/ 1 to about 200/ 1.

Still another embodiment of this invention comprises lubricating oils, and fuels containing them in the above defined ratios, wherein the oil contains an organotin sulfide of the type and amount described and wherein the oil additionally contains an antioxidant in amount sufficient to protect the fuel and the oil against oxidative deterioration. This amount of antioxidant usually ranges between about 0.05 and about 5 percent by weight of the oil.

The preferred types of antioxidant for use in this invention are alkyl phenols. Such phenols include mononuclear dialkyl and trialkyl phenols such as 2,6-di-tertbutylphenol, 2, ,6-tri-tert-butylphenol and 2,6 di tertbutyl-4-methylphenol. Polynuclear phenols wherein two dialkylphenol moieties are linked together through the ortho or para carbon atoms via alkylene groups or sulfur atoms may also be used. Particularly outstanding antioxidants for use in this invention include 4,4'-methylenebis(2,6-dialkylphenols) wherein all the alkyl groups are branched on the carbon atoms alpha to the benzene nucleus and contain 3 to 8 carbon atoms. An outstanding example is 4,4'-methylenebis(2,6-di-tert -butylphenol). When such bisphenols are used, a preferred concentration, in the oil, lies between 0.05 and about 2 percent by weight based on the weight of the oil. In addition, amine antioxidants and amino phenol types may be employed.

In order to show the benefits derived from this invention, tests were conducted on a 40 horsepower outboard two-cycle, spark ignition engine. The engine was a current model representative of outboard marine engines in actual use. The test was conducted for a total of 120 hours, during 40 of which the engine was running and during of which it was shut down. The engine was run in eight-hour periods and then allowed to rest for sixteen. The engine was run in a large water tank. At the beginning of each test, new spark plugs were installed in the engine and new piston rings were placed on each cylinder, after having been carefully weighed. At the completion of the test, the piston rings were re- 'moved and reweighed to determine the amount of piston ring weight loss, which is a measure of the wear caused by running the engine.

In each of the following tests the oil employed was a commercially available, specially blended lubricating oil recommended by the manufacturer as a two-cycle outboard lubricant. The oil had a viscosity of 857 SUS at F. and 78.4 SUS at 210 F. and a viscosity index of 88.0. Before the test, the oil contained 0.2 percent sulfur and had an acid number of 0.5. An analysis of the oil showed that it contained no barium, phosphorus, zinc, or chlorine and only a trace of calcium. The fuel employed to operate the engine in these tests was a blend of commercially available, regular automobile-type gasoline and contained 24.5 percent aromatics, 3.5 percent olefins, 72 percent saturated hydrocarbons and 0.02 percent sulfur by weight. The gravity of the fuel by ASTM Procedure 'D-287 was 59.5 API and the fuel had a vapor pressure of 8.3 p.s.i. when determined according to ASTM Procedure D-323. The initial boiling temperature of the fuel was 103 F. and the final boiling point was 405 F. The fuel essentially contained 3 ml. of lead/ gallon as tetraethyllead (Motor Mix) and had a Motor Octane Number (AST M Test D-908) of 100.6.

Various blends of the above fuel and oil were prepared both with and Without an organotin sulfide additive of this invention at varying concentrations. These fuel/ oil mixtures were then employed in the outboard engine according to the above procedure to demonstrate the spectacular reductions in piston ring wear accomplished with very small amounts of tin compounds according to this invention.

The fuel/oil ratios varied from 24:1 to 100:1. In the 100:1 fuel/oil ratio tests, varying concentrations of the tin compound were employed. The six piston rings (-three in each of the two cylinders) were weighed before and after each test, so that the average weight loss caused by wear during the test could be determined. The following results Were obtained:

EXAMPLE 1 To 100 parts of Oil A is added 0.01 part of dibutyl tin sulfide. This additive-containing oil is then blended with Fuel A in a fuel/oil weight ratio of 15/ 1.

At a fuel/ oil ratio of 100/l, with no organotin com- EXAMPLE pound present the average weight loss of the six r ngs in To 100 parts of on D is added 5 parts of dihexyl tin the two cylinders was 51.1 mg. When the ituel/oil ratio Sulfide and 0.5 part of 44, met hy1enebis(26 di tert buty1 was decreased to 24/1 the corresponding figure was 33.6 phenol). This composition is blended with Fuel 0 in mg. When the composition contained an organotin fuel/oil ratio of 75/1 to provide a low wear two-cycle fi-de of this invention, present to the extent of 0.25 weight fuel Composition percent based on the amount of oil used, the weight loss EXAMPLE 3 at a fuel/O11. i of 130/1 5; ig f To 100 parts of OilB is added 3 parts of tribenzyl tin amount fin 3 j t g ase monosulfide and 1 part of calcium petroleum sulfonate. 'i the Weght i 3 at Ffi f' This composition is blended with Fuel F in fuel/oil ratio tr g; 22 percent 0 t e fin compoun e Welg t of 200/ 1 to provide a low wear composition of this invenwas tion. If we define the average weight loss per cylinder at a EXAMPLE 4 fuel/ oil ratio of 24/1 as 100 percent We see that increas- Th U 0 e procedure of Example 3 is followed except that the zf i h filial/O11 g g t g gg $2 2 33? organotin compound is methyl tin hydrosulfide and the 1 i Increase 15 0 p y detergent is a copolymer of lauryl methacrylate and N,N- oil ratio of 100/ 1 but adding 0.25 percent of the organotin dimethylaminoethyl methacrylate sulfiide reduces the wear to 130 percent of the nonadditive 24/1 value; 0.5 percent of the tin compound re- EAAMPLE 0 duces it to 114 percent and 1.0 percent of the tin com- To 100 parts of Oil F is added 1 part of dibutyl tin pound reduces the wear to 108 percent of the 24/1 fuel/ 25 sulfide, 2.8 parts of a detergent made up of a mixture oil ratio with no additive. of octanoic acid and its amide with sec-octyl amine, 0.5 It is readily seen, therefore, that through use of the part of 4,4'-methylenebis(2,6-di-tert-butylphenol), and organotin compound of this invention it is possible to 1.7 parts of ethylene dibromide. This is blended with use a fuel/oil ratio of 100 /1 and sustain substantially Fuel B in fuel/oil ratio of 15/1 and in fuel/oil ratio only the wear which is experienced at a fuel/oil ratio of 30/1. of only 24/1 with no tin compound present. EXAMPLE 6 It is possible, through the use of this invention, to use To 100 parts of Oil G are added 1.5 parts of triphenyl fuel/oil ratios as high as 200/1 and still achieve good ti tri lfide and 0,5 part of ethylene dim-amide. This Wear benefits. composition is blended with Fuel D in fuel/oil ratio The compositions of this invention are illustrated by 39 of 80 1, the following examples, in which 'all parts and percentages EXAMPLE 7 l are by weight unless otherwise designated. The oils and To 100 parts of Oil A are added 1 part of dibutyl tin fuels used in preparing the compositions are identified in sulfide and 1.5 Parts of H16 amide 0f decanoic a d With Tables II and III as follows: secondary decyl amine. This composition is blended 40 with Fuel B in fuel/oil ratio of /1.

TABLE II Typical lubricating oils of this invention Viscosity sUs at Viscosity Percent Percent Percent Percent Percent Oil Index. Sulfate Barium Calcium Phos- Zinc F 210 F. phorus A 307 54. 3 10s. 5 B--. 452 61.8 98.5 0.4 0.10 Trace 0.040 0.051 C 749 50.5 4.0 0.2 Trace D-.. 698 03.7 52.0 0.4 0 30 Trace 718 58.4 2.5 0.2 Trace 1 501 86.8 120.5 0.30 0.80 Trace G--. 484 68.0 110.0 1.5 0.052

TABLE III Typical leaded fuels of this invention Initial Alkyllead, Gravity. Boiling Research Fuels mL/galloii API Temper- Octane Arorna- Olefius Saturates ture, Number tics A 3.13(TML) 59.0 03 g 22.5 30.5 47.0 13.-.-.- 2.58 (TEL) 00.2 93 25.5 14.0 00.5 o 0.05 (TEL) 00.0 04 3.5 0.0 05.5 D 0.84 (TEL) 58.4 100 34.0 23.5 41.0 E 1.50 (TML) 03.3 91 92.8 15.0 27.5 57.5 F 1.48 (Mixture) 04.3 05 02.9 9.5 28.0 52.5

(When alkyllcad is present, it is formulated as Motor Mix). TML=tetran1ethyllead. TE L =tetraethyllead.

EXAMPLE 8 To the oil of Example 7 is added 1.0 percent by weight of ethylene dibromide. This composition is blended with Fuel A in fuel/ oil ratio of 140/ 1.

EXAMPLE 9 To the oil of Example 8 is added 1.5 percent of 4,4- methylenebis(2,6-di-tert-butylphenol). This composition is blended with Fuel C in the fuel/oil ratio of 100/1.

We claim:

1. A fuel/oil mixture especially adapted for use in two-cycle engines, said mixture comprising a major proportion of leaded hydrocarbon fuel of the gasoline boiling range, from about 0.5 to 6.2 percent by weight of hydrocarbon lubricating mineral oil, and from about 0.005 to about 0.62 percent by weight of an oil-soluble sulfur-containing organotin compound having at least one carbon-to-tin. bond and at least one non-ionic sulfur-totin bond and having the formula where p is an integer of from 2-3; R is a hydrocarbon radical of from 3-18 carbon atoms when p is 2and from 1-18 carbon atoms when p is 3; andq is 1 when R has at least three carbon atoms and is 3 when R has from 1-2 carbon atoms.

2. A composition especially adapted for blending with two-cycle engine fuel, said composition comprising a major proportion of hydrocarbon mineral lubricating oil, and from 0.1 to 10.0 Weight percent of an oil-soluble sulfur-containing organotin compound having at least one carbon-to-tin bond and at least one non-ionic tin-to-sulfur bond, and having the formula [(R'psn) 1 -1 a where p is an integer of from 2-3; R is a hydrocarbon radical of from 3-18 carbon atoms when p is 2 and from 1-18 carbon atoms when p is3; and q is 1 when R has at least three carbon atoms and is 3 when R has from 1-2 carbon atoms, and an oil-soluble detergent in amount suflicient to substantially reduce sludge formation in the two-cycle engine, said detergent being an amide having the formula R1 RJLN Where R is an aliphatic hydrocarbon radical of 5-9 carbon atoms and R and R are aliphatic hydrocarbon radicals of 6-10.

3. A composition especially adapted for blending with two-cycle engine fuel, said composition comprising a major proportion of hydrocarbon mineral lubricating oil, from 0.1 to 10.0 weight percent of dibutyl tin sulfide, and from 0.5 to 5 weight percent of an amide having the formula where R is an aliphatic hydrocarbon radical of 5 to 9 carbon atoms and R and R are aliphatic hydrocarbon radicals of 6-10 carbon atoms.

4. A composition especially adapted for blending with two-cycle engine fuel, said composition comprising a major proportion of mineral lubricating oil, from about 0.1 to 10.0 weight percent of dibutyl tin sulfide, from about 0.5 to 5 percent of an amide having'the formula where R is an aliphatic hydrocarbon radical of 5 to 9 carbon atoms and R, and R are aliphatic hydrocarbon radicals of 6-10 carbon atoms, and from 0.5 to 7.5 weight percent of ethylene dibromide.

5. A fuel/oil mixture especially adapted for use in two-cycle engines, said mixture comprising a major proportion of leaded hydrocarbon fuel of the gasoline boiling range, from about 0.5 to about 6.2 percent by weight of hydrocarbon mineral lubricating oil, from about 0.005 to about 0.62 weight percent of an oil-soluble sulfur-containing organotin compound having at least one carbonto-tin bond and at least one non-ionic sulfur-to-tin bond and having the formula mammals].

where p is an integer of from 2-3; R is a hydrocarbon radical of from 3-18 carbon atoms when p is 2 and from 1-18 carbon atoms when p is 3; and q is 1, when R has at least three carbon atoms and is 3 when R has from 1-2 carbon atoms, and from about 0.125 to about 0.62 percent by weight of an oil-soluble detergent, said detergent being an amide having the formula fl) /R1 RO-N where R is an aliphatic hydrocarbon radical of 5-9 carbon atoms and R and R are aliphatic hydrocarbon radicals of 6-10 carbon atoms.

6. A fuel/oil mixture especially adapted for use in twocycle engines, said mixture comprising a major proportion of leaded hydrocarbon fuel of the gasoline boiling range, from about 0.5 to about 6.2 percent by weight of hydrocarbon mineral lubricating oil, from about 0.005 to about 0.62 weight percent of an oil-soluble sulfurcontaining organotin compound having at least one carbon-to-tin bond and at least one non-ionic sulfur-to-tin bond and having the formula Where p is an integer of from 2-3; R is a hydrocarbon radical of from 3-18 carbon atoms when p is 2 and from 1-18 carbon atoms when p is 3; and q is 1 when R has at least three carbon atoms and is 3 when R has from 1-2 carbon atoms, and from about 0.75 to about 2.5 theories, based on the amount of lead present, of an hydrocarbon halide scavenger, said halide being selected from chlorine and bromine.

7. The composition of claim 6 wherein said organotin compound is dibutyl tin sulfide.

8. A fuel/ oil mixture especially adapted for use in twocycle engines, said mixture comprising a major proportion of leaded hydrocarbon fuel of the gasoline boiling range, from about 0.5 to about 6.2 percent by weight of hydrocarbon mineral lubricating oil, from about 0.005 to about 0.62 weight percent of an oil-soluble sulfurcontaining organotin compound having at least one carbon-to-tin bond and at least one non-ionic sulfur-to-tin bond and having the formula Where p is an integer of from 2-3; R is a hydrocarbon radical of from 3-18 carbon atoms when p is 2 and from 1-18 carbon atoms when p is 3; and q is 1 when R has at least three carbon atoms and is 3 when R has from 1-2 carbon atoms, and from about 0.00025 to about 0.3 percent by weight of a 4,4-methy1enebis(2,6-dialkylphenol) wherein all the alkyl groups are branched on the carbon atoms alpha to the benzene nucleus and contain 3 to 8 carbon atoms.

9. A fuel/oil mixture especially adapted for use in twocycle engines, said mixture comprising a major proportion of leaded hydrocarbon fuel of the gasoline boiling range, from about 0.5 to about 6.2 percent by weight of hydrocarbon mineral lubricating oil, from about 0.005 to about 0.62 percent by weight of dibutyl tin sulfide,

11 from about 0.125 to about 0.62 percent by where R an aliphatic hydrocarbon radical of 5 to 9 carbon atoms and R and R are alipahtic-hydrocarbon radicals of 6 to 10 carbon atoms, from about 0.00025 to about 0.3 percent by weight of 4,4'-methylenebis(2,6-ditert-butylphenol) and from about 0.75 to about 2.5 theories, based on the amount of lead present, of ethylene dibromide.

10. A composition especially adapted for blending with two-cycle engine fuel, said composition comprising a major proportion of hydrocarbon mineral lubricating oil, from about 0.1 to 10.0 Weight percent of dibutyl tin sulfide and from about 0.5 to about 7.5 percent by weight of ethylene dib-romide.

11. A composition especially adapted for blending with two-cycle engine fuel, said composition comprising a major proportion of hydrocarbon mineral lubricating oil, from about 0.1 to 10.0 weight percent of dibutyl tin sulfide and from about 0.05-5 percent by weight of 4,4'-methylenebis 2,6-di-tert-butylphenol) 12. A fuel/oil mixture especially adapted for use in two-cycle engines, said mixture comprising a major proportion of leaded hydrocarbon fuel of the gasoline boiling range, from about 0.5 to about 1.65 percent by weight of hydrocarbon mineral lubricating oil and from about 0.005 to about 0.62 percent by weight of an oil-soluble sulfur-containing organotin compound having at least one carbon-to-tin bond and at least one non-ionic sulfur-totin bond and having the formula where p is an integer of from 2-3; R is a hydrocarbon radical of from 3-18 carbon atoms when p is 2 and from 1-18 carbon atoms when p is 3; and q is 1 when R has at least three carbon atoms and is 3 when R has from 1-2 carbon atoms.

13. The composition of claim 12 wherein said organotin compound is dibutyl tin sulfide.

14. The composition of claim 1 wherein said organotin compound is a dialkyl tin sulfide.

15. The composition of claim 14 wherein said organotin compound is dibutyl tin sulfide.

References Cited by the Examiner UNITED STATES PATENTS 1,649,485 11/1927 Orelup I- 44-66 1,692,784- 11/1928 Orelup et a1. 4466 2,181,914 12/1939 Rosen 25246 .4 3,036,972 5/1962 Antler. 3,043,775 6/1962 Ooflield et a1. 4478 3,058,912 10/1962 Antler 252-49.6 3,063,943 1l/1962 Antler 252464 3,077,451 2/1963 Antler 25246.4

FOREIGN PATENTS 795,390 5/1958 Great Britain.

- 795,658 5/1958 Great Britain.

DANIEL E. WYMAN, Primary Examiner.

Y. M. HARRIS, Assistant Examiner. 

1. A FUEL/OIL MIXTURE ESPECIALLY ADAPTED FOR USE IN TWO-CYCLE ENGINES, SAID MIXTURE COMPRISING A MAJOR PROPORTION OF LEADED HYDROCARBON FUEL OF THE GASOLINE BOILING RANGE FROM ABOUT 0.5 TO 6.2 PERCENT BY WEIGHT OF HYDROCARBON LUBRICATING MINERAL OIL, AND FROM ABOUT 0.005 TO ABOUT 0.62 PERCENT BY WEIGHT OF AN OIL-SOLUBLE SULFUR-CONTAINING ORGANOTIN COMPOUND HAVING AT LEAST ONE CARBON-TO-TIN BOND AND AT LEAST ONE NON-IONIC SULFUR-TOTIN BOND AND HAVING THE FORMULA 